The present invention relates generally to eye-wear and more particularly to eye-wear using magnets for attachment.
Auxiliary frames with lenses have been used for decades to augment deficiencies in primary frames. For example, the auxiliary frames may be for magnifying purposes, or may transform the primary frames into sunglasses.
For decades, people around the world have been creating numerous ingenious methods to attach the auxiliary frames onto the primary frames. In one line of approaches, the auxiliary frames are clipped onto the lenses of the primary frames. Not only do such clips obstruct the wearer's vision, they may scratch the lenses of the primary frames. To alleviate the defect of view obstruction, there are designs using small clips at the edges of the frames. However, these small clips still create scratches on the lenses and the primary frames, and attaching these auxiliary frames with small clips requires some maneuvering with two hands, and it would not be easy to do so, for example, if one is driving. Also, to detach such an auxiliary frame from its primary frame, one typically have to push down at its bridge and warp the frames outward on both sides of the lenses. It is not uncommon for such actions to permanently deform the auxiliary frame.
Another approach uses two pairs of magnets instead of clips, with one pair on the primary frame and the other on the auxiliary frame. The magnets are located on the plane of the lenses, and are close to the temples of the frames. Since they are on the plane of the lenses, they have to be carefully designed so that they can blend into the general style of the frame, without being too conspicuous. One way is to make the magnets very small. With gravity pulling the auxiliary frame away from its primary frame, the magnets have to be of certain size so as to have sufficient magnetic power to hold the auxiliary frame to the primary frame.
One reason for the magnets to be close to the temples is that the pair of magnets on a frame should be as far apart as possible. This is to ensure the auxiliary frame to be right over the primary frame, not only at the locations close to the bridges of the frames, but also at the locations close to the arms of the frames. However, in order to have sufficient coupling power, the magnets on the auxiliary frame have to match in both locations and orientations to the magnets on the primary frame. This is not an easy task, especially because the magnets are typically very small for stylistic reasons.
The further away the pair of magnets are on a frame, the more difficult it is to align them in both locations and orientations to magnets on another frame. First, imagine the magnets in a primary frame are slightly off in locations from those in an auxiliary frame. Since the magnets are quite small, slight misalignment in the locations would significantly reduce magnetic coupling between the frames. Next, imagine one small magnet in the primary frame is different in orientation from its corresponding magnet in the auxiliary frame. This can happen, for example, if the auxiliary frame has been slightly twisted--the magnitude of the difference is proportional to the distance between the pair of magnets on the frame. Two magnets may not even be able to couple together if they have different orientations. Misalignment in locations or orientations not only adversely affects the coupling power of the auxiliary frame to the primary frame, but also creates an unpleasant outward appearance for the wearer, especially when the auxiliary frame is tilted relative to the primary frame.
It should be apparent from the foregoing that there is a need for improved methods and apparatus to attach auxiliary frames to primary frames so that auxiliary frames can be easily, firmly and elegantly attached to primary frames.